It used to be an underground hobby. People did it, but nobody talked about it—not only because it was embarrassing to admit that you coveted Charlton Heston’s slave collar from Planet of the Apes but also because, since such things were studio property, it was illegal to own them. Shady studio insiders and a cabal of collectors struck deals in private. That all changed in 1970, when MGM cleared some clutter from its soundstages with a three-day auction. Among the frayed costumes and antique furniture that hit the block were two of the most important sci-fi props ever made: the proto-steampunk contraption from the 1960 film adaptation of H. G. Wells’ The Time Machine, and the miniature model of the United Planets Cruiser C-57D, better known as the Forbidden Planet flying saucer. The time machine sold for almost $10,000, and while there’s no record of what the silver saucer went for then, it changed hands eight years ago for $76,700. Since MGM’s auction, prices for the best sci-fi props have routinely hit six-figures. In October 2015, the miniature Rebel blockade runner ship from Star Wars: Episode IV pulled down $450,000.

This very expensive hobby is about more than snatching up the coolest specimens. It’s about lost youth, self-identification, preserving the past, and—though most collectors won’t admit it—hero worship and secret cosplay. There are some things in life more thrilling than watching your favorite movie late at night while clutching a screen-used prop from the same flick in your trembling, sweaty palms, but it’s a very short list.

When the Blade Runner gun surfaced, it was a big deal for the sci-fi prop community. After 24 years without a sighting, enthusiasts had resigned themselves to the idea that Deckard’s hand cannon was lost forever, like tears in rain. Then suddenly there it was, at the 2006 Worldcon, displayed under glass in all its off-world glory. Using 170 forensic photographs documenting every screw, scratch, and rust spot, hardcore collectors on the RPF hobbyist website were able to make a positive ID. Not only was this an authentic BR gun, it was the authentic “hero” blaster—hero being prop lingo for the detailed model used in close-ups—the very same weapon Harrison Ford used to blow away replicants. Three years later, Deckard’s PKD (a sly nod to Philip K. Dick, the author of Blade Runner’s source material) sold at auction for $270,000. The winning bidder was Dan Lanigan, a burly TV producer known for bidding up lots that pass the “mom test,” props so indelibly iconic that even your mother would recognize them. The allure of this hero blaster is that, unlike so many sci-fi heaters, it looks and feels like a real gun. That’s because it’s made with real gun parts. The steel slab atop the barrel and the magazine below are from a .222-caliber Steyr-Mannlicher SL bolt-action target rifle (the factory serial number is clearly visible: 5223). The other primary donor organs were pulled from a Charter Arms Bulldog .44 Special. This inspired mix of high- and low-tech components strikes the perfect balance between dystopian sci-fi and gumshoe noir.

The protagonist of Paul Verhoeven’s sleeper hit is Officer Murphy, the titular cyborg tasked with cleaning up the mean streets of Detroit. But the character that really steals the show is the dysfunctional and heavily armed homicidal bot known as ED-209. Whether blowing away a brown-nosing junior executive with 20-mm cannons or throwing a big-baby tantrum after falling down a flight of stairs, ED’s screen presence is a paragon of stop-motion animatronics. Collector Dan Lanigan purchased his ED-209 model directly from RoboCop’s VFX supervisor, Phil Tippett. It’s one of only two fully articulating ED-209 miniatures made for this underrated cyberpunk satire, and the only one reused for Robocop 2 and 3. A cross between a Bell UH-1 Huey gunship and a DARPA black project, this 8-inch-tall maquette is an exact dupe of the full-size (7-foot-tall, 300 pound) but mostly static fiberglass ED-209 that Verhoeven used for the live-action scenes. An obsessive attention to detail—from the four hydraulic rams controlling each leg to the heat exchangers, intake/exhaust vents, and radiators (homages to ED’s Motor City roots)—was necessary so that the lighting would reflect at exactly the same angle and intensity on both the puppet and it’s full-size counterpart. If the metrics were slightly off, the stop-motion and live-action footage wouldn’t match up perfectly in post-production. Hinged and ball-and-socket joints enable the many slight and precise body movements necessary for convincing stop-action photography. It’s not just the historical significance, though, that gets collectors excited. “ED is a badass Corvette with legs,” Lanigan says. “He’s a villain, but also likeable because he’s such a comical idiot.”

In the world of vintage collectables, there’s always a marquee brand that demands insane prices. In the sci-fi prop world, that brand is Star Wars. The prices for production artifacts with a Lucasfilm provenance make a mockery of presale estimates. A TIE Fighter miniature from Star Wars: A New Hope sold for $402,500, nearly twice the expected price. More impressive, back in 2005, a lightsaber used by Mark Hamill in the same film sold for $200,600, three times its estimate. That first-gen weapon (the one lost along with most of Luke’s forearm in the showdown with Vader at Cloud City) was fashioned by set decorator Roger Christian out of an old flashgun handle for a Graflex camera, along with other doodads. This one, Luke’s green-bladed Excalibur, was a new design crafted for Jedi. But this saber wasn’t built piece by piece—it’s a casting. In this process, a silicone mold is made of the original prop, then that mold is used to produce identical copies in hard rubber, resin, and even metal. Castings are often used in place of hero props in stunt scenes so the detailed original doesn’t get damaged. This resin casting was used in the Sarlacc sequence at the Great Pit of Carkoon.

Every generation has its childhood demons. The release of The Terminator in 1984 introduced a new bogeyman to the silver screen (and VHS): the T-800. Seven years later, the film’s sequel, Terminator 2: Judgment Day, cemented the reputation of the crimson-eyed grim reapers. Only four of these “puppets” were made for T2: two articulating heroes (capable of gross body movement, plus head and facial movement), and two “stunts” (nonarticulating, but designed to take more punishment). An original, full-scale T-800 endoskeleton sold at auction in 2007. Bidding started at $80,000 and topped out at $488,750, crushing the pre-auction high estimate of $120,000. Why so much for a shiny puppet? Because it was a screen-used hero T-800, one of the models that saw action when the cameras were rolling. Also, the T-800 happens to be Stan Winston’s Mona Lisa. The late designer’s FX wizardry is part of Hollywood lore: Jurassic Park III, Aliens, Predator, Predator 2, A.I., Edward Scissorhands. One of his four Oscars (Best Visual Effects, 1992) is thanks to this 6′ 2″ animatronic skeleton. The second-gen T-800 is made mostly of plastic that’s been electroplated. How do you electroplate a nonconductive material like plastic? By spraying the plastic with a high-particulate, conductive copper paint, then submerging the pieces in an electroplating bath, first nickel, then chrome. Although this added more weight to the puppets, it made the finish more durable. Huge weight savings were realized elsewhere—50 pounds’ worth—because the harder exterior eliminated the need for internal steel supports. This light and nimble design allowed a puppeteer to crash a stunt T-800 through a breakaway wall or wreak havoc on the Future War battlefield without having to worry about bits of chrome flaking off. Sweet dreams, puny humans.

There’s no denying the cultural significance of Ghostbusters. Now more than three decades old, the original film still resonates like a giant tuning fork. Which goes a long way toward explaining why the proton pack is so revered by prop collectors. After all, who wouldn’t want their own portable unlicensed nuclear accelerator? Inspired by a military-issue flamethrower, “hardware consultant” Stephen Dane purchased a backpack frame from an army surplus store in Hollywood and made a rough prototype. After director Ivan Reitman added his tweaks, a cinematic legend was born. The molded fiberglass shell is attached to an aluminum backplate, which was then bolted to a US Army–spec backpack frame. Dane added paint, aluminum warning labels (“Danger: High Voltage 1KV”), flashing lights, crank knobs, and enough electronic parts to make the thing pop onscreen. Most of those components have been identified thanks to hi-res photos on prop sites: Sage and Dale resistors, Clippard pneumatic tubing, Arcolectric indicators, and Legris banjo bolts (on the neutrona wand). It’s as heavy as it looks—with the battery, a hero weighs more than 30 pounds. To ease the load on the actor’s shoulders, two lighter versions were available for use during filming: a gutted “semi-hero,” with some cast surface details (for wide shots) and a bantam-weight “stunt” made of foam rubber (for action scenes). Four years ago, a screen-used hero proton pack was added to the Lanigan collection. Price: $169,900. Congrats Dan, but remember: Don’t cross the streams. It would be bad.

Stanley Kubrick’s masterful tale of human evolution catapulted the humble sci-fi genre from B-movie fodder to serious art, thanks largely to the groundbreaking visuals pioneered by the auteur director and his FX master, Douglas Trumbull. The miniature models used in the eerily realistic space travel scenes are of particular interest to collectors because of their intricate design—aerospace engineers were consulted on the production of each model. Most of the original props were destroyed, but one of the 2001 miniatures survived: the screen-used Aries shuttle that transports Dr. Heywood R. Floyd from the space station to the Clavius excavation site on the moon. In 1975, the prop found its way to one of Kubrick’s neighbors, a Hertfordshire public school teacher, who used it as a show-and-tell exhibit for art students. When the prop was eventually consigned to auction in 2015, the final paddle price greatly exceeded the expected high mark of $100,000. The winning bid, at $344,000, was the Academy of Motion Picture Arts and Sciences. It will be restored before being displayed at the new Renzo Piano-designed Academy Museum, which opens in 2018. The hulking Aries model—it weighs about 100 pounds and measures 94 inches in circumference—is made of wood, blown plexiglass, and various metals, finished with plastic bits cherry-picked from off-the-shelf scale-model kits. These hobby-model parts provide the detail, texture, and depth necessary for close-up FX photography with large-format cameras. Look closely and you’ll also see wires, tubing, flexible metal foils, decals (“Battery Location Point Here”), and plenty of heat-formed plastic cladding. Although the internal mechanicals were removed many years ago, the gears that control the four landing legs still function flawlessly. The virtuosic scene in 2001 starring this long-lost orb is the reason Mission Control still has The Blue Danube Waltz in heavy rotation on its wake-up playlist for ISS astronauts.

There are plenty of bogus or knockoff Star Trek props in circulation, but there’s nothing fake about this original series phaser. The provenance is stellar: purchased by a prop artist directly from Paramount in the 1970s. It’s an ultra-rare hero constructed mostly of aluminum, fiberglass, and cast resin. The handle is a hand-painted brass tube embellished with popsicle sticks. (Yes, really. Look closely.) There were other phasers made, including midgrade fiberglass models for longer shots and VacuForm plastic ones for Kirk to use when clubbing Klingons. But this is the most intricate variant used for close-ups. Only two were made, so this specimen is worth a bundle. The owner isn’t selling anyway. It’s part of a massive sci-fi prop collection that includes classics like a prized space suit from 2001. If you must have a phaser of your own, there’s always the forgery market.

Some props are sketched by a conceptual artist and painstakingly assembled by union craftspeople piece by piece. Many more, though, are simply castings. This is particularly true of movie prop firearms. Matt Damon can’t pistol-whip a bad guy with a real Sig Sauer 9-mm hero gun in The Bourne Identity. A “live gun” is used strictly for close-ups and shooting blanks, where filming anything but an actual Sig just won’t do. To pull off a pistol-whip scene, the prop department must cast a Sig Sauer stunt gun out of soft rubber. Guns are also cast in hard rubber, resin, and even metal depending on what function they need to serve in the film. In the prop collecting community, castings and recastings (castings of castings) are highly contentious subjects. “If you look for cheap movie prop kits or ‘raw castings’ on eBay, you’ll find hundreds of people all over the world who bought some shitty rubber prop and made it shittier by recasting it,” says former Lucasfilm VFX designer and MythBusters host Adam Savage. “Because every time you cast something, each successive generation gets crappier.” So when Savage decided to add the comically oversized Samaritan handgun to his prop collection, he went straight to the source: Guillermo del Toro, director of the Hellboy franchise. Unlike a lot of iconic props, there aren’t many genuine Samaritan castings on the market. Del Toro owns the only hero Samaritan, which was cast in aluminum by the famous Weta Workshop in New Zealand. He also had a spare screen-used hard rubber Samaritan casting, which he traded straight up for a casting of Adam Savage’s immaculate scratch-built Blade Runner PKD blaster. A perfect clone of visual designer TyRuben Ellingson’s original concept for the film, the Samaritan is one of the heaviest stunt handguns ever cast. “My Samaritan weighs 5 or 6 pounds,” Savage says proudly. “Guillermo had the stunt guns cast in hard rubber because he wanted them to feel heavy when [Hellboy star] Ron Perlman picked them up.” The Weta detailing is so accurate that this thing could pass for the hero Samaritan in a tight shot. “The gravitas and veracity of this prop is exceptional,” Savage says. “It feels luxurious to hold.”

Rene Chun is a frequent WIRED contributor. He wrote about the SFMOMA redesign in issue 24.05.